Knoevenagel condensation reaction in supercritical carbon dioxide medium using a Zn(II) coordination polymer as catalyst

•1D Zn(II) coordination polymer (Zn-CP 1) was synthesized by solvothermal reaction.•Zn-CP 1 was tested as a catalyst in the Knoevenagel condensation of benzaldehyde and malononitrile under scCO2.•Protic co-solvents (e.g., H2O) exhibited a promoting effect in the catalytic reaction.•Catalyst can be recycled without a considerable loss of activity, displaying structural stability throughout catalytic process.